Mod bit / BUR
Asphalt roofs alligator, shed granules and open at the laps. Prime the surface, reinforce the weak spots and cover the whole field with a membrane that does not need a torch.
- Pr355 · Pr315Asphalt primers
- No torchCold-applied restoration
What happens to mod bit and BUR
Modified bitumen and built-up roofs oxidize from the top down. Granules shed, the exposed asphalt alligators and the cap sheet opens at the laps and flashings.
Bleed-through and adhesion are the two problems a coating has to solve here, which is why every asphalt system starts with a primer and why a granulated cap sheet takes more material per square than a smooth one. Gravel BUR is a candidate once the gravel is off and the surface is primed.
A coating job when
- Cap sheet adhered, laps repairable
- Alligatoring shallow — no exposed felts
- Insulation dry on a moisture scan
- Smooth or granulated surface, gravel removed
Not a coating job when
- Blisters and ridges across the field
- Wet insulation or saturated felts
- Gravel that cannot be removed
Not sure? Send photos and a core cut. A rep will call it.
The build-up, in order.
For asphalt roofs that pond. One primer, one mastic, one high-solids topcoat.For well-drained asphalt roofs. Pr355 blocks bleed-through; fabric turns an alligatored field into a reinforced membrane.
Clean & prep
Scrub with Pr325 cleaner diluted 1:4, keep it wet for 15 minutes, then power wash at 2,000 psi or more and rinse to clean water. Let it dry. Replace wet insulation flagged on the moisture scan. Pull-test a 2 × 2 ft patch before you order. Cut and patch blisters. Spud gravel from BUR before anything else.
Prime
Bleed-blocking primer at 1 to 1.5 gal per 100 ft²; alligatored cap sheet takes more. Dries yellow to amber — wait 24 to 48 hours before silicone. Switch to Pr355 where bleed-through is severe.
Pr315 Bleed-Blocking Primer1 gal / 80 ft²Seams & details
Mastic and fabric over open laps, flashings, drains and penetrations.
Si790 Silicone Mastic1 gal / 60 lin ftWalkways
Around units and along service paths, set into wet topcoat and clipped at the corners.
GripTite Walkway Pad Walkway ProtectionSized to layout
Clean & prep
Scrub with Pr325 cleaner diluted 1:4, keep it wet for 15 minutes, then power wash at 2,000 psi or more and rinse to clean water. Let it dry. Replace wet insulation flagged on the moisture scan. Pull-test a 2 × 2 ft patch before you order. Cut and patch blisters. Spud gravel from BUR before anything else.
Prime
Jet-black general-purpose primer over the whole field at ½ gal per 100 ft². Blocks bleed-through under white acrylic.
Pr355 General-Purpose Primer1 gal / 200 ft²Seams & details
Fibered mastic and fabric at laps, flashings and penetrations.
Ac595 Acrylic Mastic1 gal / 40 lin ftFull-field fabric
Optional · offEmbed polyester across the whole field in wet base coat where alligatoring is general.
Fibered Polyester Fabric Reinforcing Fabric900 ft² per roll · rule of thumbTopcoat
Second full coat at right angles to the first.
Ac550 Acrylic Roof Coating8.5 dry mils per gal / 100 ft²Walkways
Around units and along service paths, set into wet topcoat and clipped at the corners.
GripTite Walkway Pad Walkway ProtectionSized to layout
- 04 · TopcoatSi750
- 03 · Seams & detailsSi790
- 02 · PrimePr315
- Substrate · Modified bitumen / BUR cap sheet
Thickness not to scale. Optional steps appear here when switched on in the estimator below.
Rough quantities for this roof.
Enter the roof and get gallons and containers for the route above. It is a planning number, not a bill of materials — your rep confirms coverage before anything ships.
Estimate
25,000 ft² · 30 dry mils · silicone- 02Pr315 Bleed-Blocking PrimerPrime · 1 gal / 80 ft²344 gal69 × 5-gal pails
- 03Si790 Silicone MasticSeams & details · 2,125 lin ft · 10 penetrations42 gal21 × 2-gal pails
- 04Si750 Silicone Roof CoatingTopcoat · 30 dry mils536 gal9 × 55-gal drums + 9 × 5-gal pails
- 05GripTite Walkway Pad Walkway ProtectionWalkways · Rolls and clipsSized to the layout — your rep quotes it
Liquid product, all steps922 gal
- Smooth surface: no texture allowance
- 10% overage on every liquid product
- Quantities rounded up to whole gallons, then to full containers
- Pr315 at 1 gal / 80 ft² — midpoint of the TDS range, 1 to 1.5 gal / 100 ft²
- Si790 at 1 gal / 60 lin ft of seam, 0.2 gal per penetration — rule of thumb
- Si750: 15.4 dry mils per gal / 100 ft² — TDS; 30 mils this coat
Rough estimate for planning. Actual coverage depends on surface porosity, texture, application method and verified mil thickness. Confirm with the TDS and your rep before ordering.
Estimate
25,000 ft² · 32 dry mils · acrylic- 02Pr355 General-Purpose PrimerPrime · 1 gal / 200 ft²138 gal2 × 55-gal drums + 6 × 5-gal pails
- 03Ac595 Acrylic MasticSeams & details · 2,125 lin ft · 10 penetrations62 gal13 × 5-gal pails
- 05Ac510 Acrylic Roof CoatingBase coat · 16 dry mils500 gal9 × 55-gal drums + 1 × 5-gal pail
- 06Ac550 Acrylic Roof CoatingTopcoat · 16 dry mils518 gal9 × 55-gal drums + 5 × 5-gal pails
- 07GripTite Walkway Pad Walkway ProtectionWalkways · Rolls and clipsSized to the layout — your rep quotes it
Liquid product, all steps1,218 gal
- Smooth surface: no texture allowance
- 10% overage on every liquid product
- Quantities rounded up to whole gallons, then to full containers
- Pr355 at 1 gal / 200 ft² — TDS
- Ac595 at 1 gal / 40 lin ft of seam, 0.3 gal per penetration — rule of thumb
- Ac510: 8.8 dry mils per gal / 100 ft² — SESCO build-up rate (the TDS states 9); 16 mils this coat
- Ac550: 8.5 dry mils per gal / 100 ft² — from 53% volume solids (the TDS states no dry-mil yield); 16 mils this coat
Rough estimate for planning. Actual coverage depends on surface porosity, texture, application method and verified mil thickness. Confirm with the TDS and your rep before ordering.
Case studies.
Case studies are on the way.
The data sheets for this route.
Published TDS and SDS for the silicone route. Ask your rep for any sheet not listed; the spec letter comes from your rep.Published TDS and SDS for the acrylic route. Ask your rep for any sheet not listed; the spec letter comes from your rep.
Order through your rep.
Reps confirm coverage and write the spec letter. Send the estimate, or call 1-812-776-6727.